1. Field of the Invention
The present invention relates to a resistor, and more particularly, to a current sensing resistor.
2. Description of the Prior Art
Current sensing resistors have been used in the electronic industry for many years, and are formed on the basis of the Kelvin theory or the 4-wire theory. The current sensing resistor is mainly used for application of low resistance, and has the advantages of low temperature coefficient and high heat dissipation performance when compared with general resistors. A conventional current sensing resistor (such as the U.S. Pat. No. 5,999,085) adopts a structure where a metal plate with fixed resistance is a middle portion and each of the two opposite terminals of the plate is fixedly connected to a side portion with high electrical conductivity. Each of the pair of side portions has a slot, dividing each of the pair of side portions into a current terminal and a sensing terminal. The length of the slot may be used for deciding the stability of resistance of the current sensing resistor.
The conventional current sensing resistor is formed through the fixed connection of different materials of metal or alloy, which is time-consuming during manufacturing and is also difficult to control the material characteristics of the metal or alloy. Moreover, other methods such as soldering or adhering are inevitably used during the fixed connection process, and the use of extra materials renders that the conventional current sensing resistor is incapable of fully demonstrating the material characteristics of a resistor substrate. As a result, the stability of resistance of the current sensing resistor is affected.
Therefore, a current sensing resistor made through an integral molding method is required in the market, allowing such current sensing resistor to be formed by only one material of metal or alloy. Therefore, the characteristics of the metal or alloy may be fully demonstrated, and it will also be easier to select the corresponding metal or alloy according to the required resistor characteristics. In this manner, manufacturing is more convenient, and the stability of resistance of the current sensing resistor is further improved.